(-)-2β-Carbomethoxy-3β-phenyltropane

(-)-2β-Carbomethoxy-3β-phenyltropane (Troparil, β-CPT, WIN-35065-2) is a stimulant drug used in scientific research. CPT is a phenyltropane based dopamine reuptake inhibitor and is derived from methylecgonidine. It is around the same potency as cocaine but lasts several times longer due to the lack of the metabolically labile ester link between the phenyl and tropane rings. The lack of an ester linkage removes the local anesthetic action from the drug, so CPT is a pure stimulant. This change in activity also makes CPT slightly less cardiotoxic than cocaine. The most commonly used form of β-CPT is the tartrate salt, but the hydrochloride and naphthalenedisulfonate salts are also available, as well as the free base.

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Uses

CPT is used in scientific research into the dopamine reuptake transporter. ³H-radiolabelled forms of CPT have been used in humans and animals to map the distribution of dopamine transporters in the brain. ^[1][2] It is also used for animal research into stimulant drugs as an alternative to cocaine which produces similar effects,^[3] but avoids the stringent licensing requirements for the use of cocaine itself.

β-CPT has similar effects to cocaine in animal studies, but no instances of this compound being abused recreationally by humans are known. Despite being easily made by the reaction of methylecgonidine with phenylmagnesium bromide, the relative scarcity of methylecgonidine and the demanding reaction conditions required for the synthesis put production of this compound beyond the capacity of most illicit drug manufacturers, and legitimate supplies of β-CPT are available only in very small quantities for a very high price.

Legal Status

CPT is legal in all countries throughout the world as of 2007. Some jurisdictions such as the USA, Canada, Australia and New Zealand might however consider CPT to be a controlled substance analogue of cocaine on the grounds of its related chemical structure.

This is somewhat unclear as there has not been any legal precedent set to determine whether a compound derived by the simplification of an illegal drug molecule (removal of an ester link in this instance) can be considered "substantially similar" to the illegal drug; all previous examples of designer drugs such as α-methylfentanyl have been derived instead by adding extra substituent groups onto the molecule, and the laws covering this area only refer to the addition or substitution of groups onto the illegal drug molecule, not their removal. An excessively broad precedent set in this area would be extremely problematic from a legal standpoint, for if Troparil is considered to be an analogue of cocaine, then ethanol would by the same ruling be an analogue of the illegal drug GHB, as ethanol is structurally derived from GHB by removal of the same functional group as troparil is from cocaine.

References

1. ^ Ritz M.C. et al. [3H]WIN 35,065-2: a ligand for cocaine receptors in striatum. J. Neurochem. 1990, 55, 1556-1562.
2. ^ Scheffel U. et al. Cocaine receptors: In Vivo Labelling with 3H-(-) cocaine, 3H-WIN 35,065-2, and 3H-WIN 35,428. Synapse 1989, 4, 390-392.
3. ^ Zakusov VV, Naumova BI. Pharmacology of troparil. Farmakologiia i Toksikologiia. 1985 Jan-Feb;48(1):15-9.